The technology relates to a vehicle body skeleton structure in which a skeleton member and a reinforcement member are joined together to thereby control a deformation mode upon receiving of external force.
In general, a skeleton or a “body skeleton” that structures a body of a vehicle such as, but not limited to, an automobile is formed through bending of steel plates into desired shapes with use of a press forming machine, etc. To fulfill predetermined rigidity necessary for the body, a reinforcement steel plate, or a so-called “reinforcement”, is joined to a region having insufficient strength in the body skeleton to reinforce the body skeleton. A joining method used to join the reinforcement steel plate may be, for example but not limited to, spot welding. The reinforcement steel plate is welded on as-needed basis in accordance with a strength required for each of a front pillar, a side rail, a center pillar, a side sill, etc., that may be non-limiting examples of such a body skeleton.
A widely-employed body skeleton has a configuration in which an outer panel and an inner panel serving as two skeleton members are joined together to form a closed cross-section, and in which the reinforcement steel plate is provided therebetween inside the space formed by the closed cross-section. The skeleton members are formed individually in advance through press forming, etc., and are joined together sequentially through a method such as, but not limited to, spot welding with those skeleton members being temporarily held at their respective predetermined positions during assembling.
For example, among the body skeletons, the center pillar is required to achieve a structure by which an upper part of the body is reinforced to have high strength such that deformation is minimized to protect occupants upon application of external force from the side due to side collision, etc., whereas a lower part of the body is reinforced such that the deformation is maximized to absorb impact energy upon the application of the external force.
Japanese Unexamined Patent Application Publication (JP-A) No. 2010-173562 discloses a technique that allows for deformation of a vehicle body skeleton, based on deformation modes that are different for respective regions in the single body skeleton, for example. In JP-A No. 2010-173562, a reinforcement steel plate joined to an outer panel of a center pillar has a lower vertical wall provided on the lower side of the reinforcement steel plate and so slanted widely as to extend inwardly in a vehicle width direction, and an upper vertical wall provided on the upper side of the reinforcement steel plate and not so slanted as compared with the lower vertical wall. Upon application of external force from the side, the lower vertical wall is so deformed and crushed as to be inclined toward a vehicle interior to absorb impact energy. Because the upper vertical wall is not so slanted as compared with the lower vertical wall, the upper vertical wall exerts resistive force against the external force upon the application of the external force from the side to prevent occurrence of large deformation toward the vehicle interior.